Extension jack



. July 1944- G. .E. BRACKETT 2,352,600

EXTENSION JACK Filed NOV. 12', 1941 A-TT RNEY.

INVENTOR.

REE E E ACKETT BY (5% Patented July 4, 1944 UNITED STATES PATENT OFFICE EXTENSION JACK George E. Brackett, San Mateo, Calif.

Application November 12, 1941, Serial No. 418,733

1 Claim.

This invention relates to improvements in extension jacks that are used for jacking up heavy bodies such as engines, pumps and other types of machinery when doing repair work.

A disadvantage in the average jack used for such work is the fact that the standard, or column, has a fixed length making it necessary for the repair man to possess a large number of different length jacks in order to properly perform the difierent kinds of work required.

An object of the present invention is to improve that type of jack by forming the standard or column out of a plurality of extension mem bers, the ends of which telescope into each other and are supported onto each other thus providing a substantial column for the jack that can be readily changed to difierent lengths.

Another object of the invention is to provide an interchangeable foot piece that can be quickly attached to any one of the extension members that form the column.

Another object of the invention is to provide an efficient fastening means for holding the extension members together by providing a circumferential groove around the upper portion of one of the members and a cotter pin through the corresponding member that is adapted to extend through the groove, and holds the members together.

Other objects and advantages will be apparent during the course of the following description.

In the accompanying drawing:

Fig. 1 is a longitudinal vertical side elevational view of one form of the improved jack involving the invention;

Fig. 2 is a longitudinal vertical sectional view taken through lines 22 of Fig. 1 looking in direction of the arrows;

Fig. 3 is a top plan of the jack;

Fig. 4 is an end sectional plan view taken through line 44 of Fig. 1, looking in direction of the arrows, the foot piece being removed.

Referring in detail to the drawing and to the different parts thereof, the numerals I, 8, and 9, designate three extension members of diiferent lengths and the numeral I0 an interchangeable foot piece that is adapted to fit onto any one of said extension members. Each of the extension members 1, 8, and 9, is preferably formed circular at the upper and lower end portions thereof, and is formed hexagon at the central portion, as shown at ll, I2, and 13, respectively, in Fig. 1. The diameters of the uppermost end portions of the extensions 8 and 9 are reduced as shown at l4 and I5, and are formed symmetrical and are adapted to telescope into the circular holes I! and I8, that are provided into the extensions 1 and 8 respectively. The extension 9 has a circular hole I9 that is symmetrical with said holes I1 and I8. Each of the extensions end portions I4 and I5 has a circumferential groove as shown at 20 and 2!. A pair of cotter pins 22 and 23 are provided and projected through the holes 24 and 25, and through the grooves 20 and 2! as shown in Figs. 1, 2 and 4. This construction affords a very simple means for holding the extension members together and eliminates much timethat would otherwise be required to connect and disconnect the same. The interchangeable foot piece It is capable of being mounted onto any one of the extension members 1, 8, and 9, and is provided with a set screw 26 for securely holding it in place. The extension members can also be held together by a set screw if desired.

The jack is provided with a suitable lifting head 21 that is formed with a threaded extension 28, a hexagon portion 29 and a hole 3|], that extends therethrough as shown in Figs. 1 and 2. The threaded extension 28, of the head 21, screws into the extension member I and is adapted to be raised or lowered by being revolved, the hole 30 providing an opening into which a suitable rod can be inserted to facilitate the revolving of the lifting head when it is desired to operate the jack. Figs. 1 and 2 shows in dot and dash outline how the lifting head raises when revolvable movement is imparted thereto.

From the foregoing it will be readily seen that the improved jack is a very useful and practical article and can have any suitable number of extension members that will give it any length desired. The foot piece It) can be mounted directly onto the extension members I to give the jack the minimum length and likewise a greater number of extension members can be provided than shown, and the foot piece in mounted onto the lowest extension to givethe jack the maximum length.

It is to be understood that the form of my invention herewith shown and described are to be taken as preferred examples of the same and that various changes relative to the material, size, shape and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claim.

Having thus described my invention, I claim:

An extension member of the character described comprising an adjustable standard, a lifting head threadedly supported therein, said standard consisting of a plurality of extension members detachably connected together and inan aperture through the female portion of each terchangeable one with the other and capable of joint and positioned to coincide with said annular providing varia'ble heights, the adjacent end porgroove on the male portion, and a pin extending tions of said interchangeable extension members through the aperture and groove to fasten each having a cooperating male and female joint, an 5 joint together. annular groove in the male portion of each joint, GEORGE E. BRACKETT. 

